soil acidification

Rainfall is naturally acidic due to carbonic acid forming from carbon dioxide in the atmosphere.{{cite web |url=https://www.epa.gov/acidrain/what-acid-rain |title=What is Acid Rain? |website=United States Environmental Protection Agency}} This compound causes rainfall pH to be around 5.0–5.5. When rainfall has a lower pH than natural levels, it can cause rapid acidification of soil. Sulfur dioxide and nitrogen oxides are precursors of stronger acids that can lead to acid rain production when they react with water in the atmosphere. These gases may be present in the atmosphere due to natural sources such as lightning and volcanic eruptions, or from anthropogenic emissions.{{cite book |doi=10.1016/B0-12-348530-4/00083-7 |chapter=Acid Rain and Soil Acidification |title=Encyclopedia of Soils in the Environment |date=2005 |last1=Blake |first1=L. |pages=1–11 |isbn=978-0-12-348530-4 }} Basic cations like calcium are leached from the soil as acidic rainfall flows, which allows aluminum and proton levels to increase.{{cite journal |last1=Goulding |first1=K. W. T. |title=Soil acidification and the importance of liming agricultural soils with particular reference to the United Kingdom |journal=Soil Use and Management |date=September 2016 |volume=32 |issue=3 |pages=390–399 |doi=10.1111/sum.12270 |pmc=5032897 |pmid=27708478 |bibcode=2016SUMan..32..390G }}{{Cite web|url=https://www.usgs.gov/news/acid-rain-effects-forest-soils-begin-reverse|title=Acid Rain Effects on Forest Soils begin to Reverse|website=www.usgs.gov|access-date=2019-03-22}}

Nitric and sulfuric acids in acid rain and snow can have different effects on the acidification of forest soils, particularly seasonally in regions where a snow pack may accumulate during the winter.{{cite journal |last1=James |first1=Bruce R. |last2=Riha |first2=Susan J. |title=Aluminum Leaching by Mineral Acids in Forest Soils: I. Nitric-Sulfuric Acid Differences |journal=Soil Science Society of America Journal |date=January 1989 |volume=53 |issue=1 |pages=259–264 |doi=10.2136/sssaj1989.03615995005300010047x |bibcode=1989SSASJ..53..259J }} Snow tends to contain more nitric acid than sulfuric acid, and as a result, a pulse of nitric acid-rich snow meltwater may leach through high elevation forest soils during a short time in the spring.{{cite book |doi=10.1007/978-1-4614-7810-2_3 |chapter=Chemistry |title=Biogeochemistry of a Forested Ecosystem |date=2013 |last1=Likens |first1=Gene E. |pages=35–87 |isbn=978-1-4614-7809-6 }} This volume of water may comprise as much as 50% of the annual precipitation. The nitric acid flush of meltwater may cause a sharp, short term, decrease in the drainage water pH entering groundwater and surface waters.{{cite journal |last1=Driscoll |first1=C. T. |last2=Schafran |first2=G. C. |title=Short-term changes in the base neutralizing capacity of an acid Adirondack lake, New York |journal=Nature |date=July 1984 |volume=310 |issue=5975 |pages=308–310 |doi=10.1038/310308a0 |bibcode=1984Natur.310..308D }} The decrease in pH can solubilize Al³⁺ that is toxic to fish,{{cite journal |last1=Cronan |first1=Christopher S. |last2=Schofield |first2=Carl L. |title=Aluminum Leaching Response to Acid Precipitation: Effects on High-Elevation Watersheds in the Northeast |journal=Science |date=20 April 1979 |volume=204 |issue=4390 |pages=304–306 |doi=10.1126/science.204.4390.304 |pmid=17800359 |bibcode=1979Sci...204..304C }} especially newly-hatched fry with immature gill systems through which they pass large volumes of water to obtain O₂ for respiration. As the snow meltwater flush passes, water temperatures rise, and lakes and streams produce more dissolved organic matter; the Al concentration in drainage water decreases and is bound to organic acids, making it less toxic to fish. In rain, the ratio of nitric-to-sulfuric acids decreases to approximately 1:2. The higher sulfuric acid content of rain also may not release as much Al³⁺ from soils as does nitric acid, in part due to the retention (adsorption) of SO₄^2- by soils. This process releases OH⁻ into soil solution and buffers the pH decrease caused by the added H⁺ from both acids. The forest floor organic soil horizons (layers) that are high in organic matter also buffer pH, and decrease the load of H+ that subsequently leaches through underlying mineral horizons.{{cite journal |last1=Singh |first1=Anita |last2=Agrawal |first2=Madhoolika |title=Acid rain and its ecological consequences |journal=Journal of Environmental Biology |date=January 2008 |volume=29 |issue=1 |pages=15–24 |pmid=18831326 }}{{cite journal |last1=James |first1=Bruce R. |last2=Riha |first2=Susan J. |title=Aluminum Leaching by Mineral Acids in Forest Soils: II. Role of the Forest Floor |journal=Soil Science Society of America Journal |date=January 1989 |volume=53 |issue=1 |pages=264–269 |doi=10.2136/sssaj1989.03615995005300010048x |bibcode=1989SSASJ..53..264J }}

{{main|Weathering#Biological weathering}}

Plant roots acidify soil by releasing protons and organic acids so as to chemically weather soil minerals.{{cite book |doi=10.1016/S0165-1250(00)80022-X |chapter=Mechanism and effect of chemical weathering of sedimentary rocks |title=Engineering Geological Advances in Japan for the New Millennium |series=Developments in Geotechnical Engineering |date=2000 |last1=Chigira |first1=M. |last2=Oyama |first2=T. |volume=84 |pages=267–278 |isbn=978-0-444-50505-7 }} Decaying remains of dead plants on soil may also form organic acids which contribute to soil acidification.{{cite book |last1=Nisbet |first1=Tom |last2=Evans |first2=C. D. |title=Forestry and Surface Water Acidification |date=2014 |publisher=Forestry Commission |isbn=978-0-85538-900-0 |oclc=879011334 }}{{pn|date=January 2025}} Acidification from leaf litter on the O-horizon is more pronounced under coniferous trees such as pine, spruce and fir, which return fewer base cations to the soil, rather than under deciduous trees; however, soil pH differences attributed to vegetation often preexisted that vegetation, and help select for species which tolerate them. Calcium accumulation in existing biomass also strongly affects soil pH - a factor which can vary from species to species.{{cite journal |last1=Alban |first1=David H. |title=Effects of Nutrient Accumulation by Aspen, Spruce, and Pine on Soil Properties |journal=Soil Science Society of America Journal |date=July 1982 |volume=46 |issue=4 |pages=853–861 |doi=10.2136/sssaj1982.03615995004600040037x |bibcode=1982SSASJ..46..853A }}

Certain parent materials also contribute to soil acidification. Granites and their allied igneous rocks are called "acidic" because they have a lot of free quartz, which produces silicic acid on weathering.{{cite book |doi=10.1017/cbo9780511920424.006 |chapter=Mutual Relations of Associated Igneous Rocks |title=The Natural History of Igneous Rocks |date=2011 |pages=110–146 |isbn=978-0-511-92042-4 }} Also, they have relatively low amounts of calcium and magnesium. Some sedimentary rocks such as shale and coal are rich in sulfides, which, when hydrated and oxidized, produce sulfuric acid which is much stronger than silicic acid. Many coal soils are too acidic to support vigorous plant growth, and coal gives off strong precursors to acid rain when it is burned. Marine clays are also sulfide-rich in many cases, and such clays become very acidic if they are drained to an oxidizing state.

Soil amendments such as chemical fertilizers can cause soil acidification. Sulfur based fertilizers can be highly acidifying, examples include elemental sulfur and iron sulfate while others like potassium sulfate have no significant effect on soil pH. While most nitrogen fertilizers have an acidifying effect, ammonium-based nitrogen fertilizers are more acidifying than other nitrogen sources.{{cite journal |last1=Wang |first1=Jing |last2=Tu |first2=Xiaoshun |last3=Zhang |first3=Huimin |last4=Cui |first4=Jingya |last5=Ni |first5=Kang |last6=Chen |first6=Jinlin |last7=Cheng |first7=Yi |last8=Zhang |first8=Jinbo |last9=Chang |first9=Scott X. |title=Effects of ammonium-based nitrogen addition on soil nitrification and nitrogen gas emissions depend on fertilizer-induced changes in pH in a tea plantation soil |journal=Science of the Total Environment |date=December 2020 |volume=747 |pages=141340 |doi=10.1016/j.scitotenv.2020.141340 |pmid=32795801 |bibcode=2020ScTEn.74741340W }} Ammonia-based nitrogen fertilizers include ammonium sulfate, diammonium phosphate, monoammonium phosphate, and ammonium nitrate. Organic nitrogen sources, such as urea and compost, are less acidifying. Nitrate sources which have little or no ammonium, such as calcium nitrate, magnesium nitrate, potassium nitrate, and sodium nitrate, are not acidifying.{{cite journal |last1=Schindler |first1=D. W. |last2=Hecky |first2=R. E. |title=Eutrophication: More Nitrogen Data Needed |journal=Science |date=8 May 2009 |volume=324 |issue=5928 |pages=721–722 |doi=10.1126/science.324_721b |pmid=19423798 |bibcode=2009Sci...324..721S }}{{cite journal |last1=Penn |first1=C. J. |last2=Bryant |first2=R. B. |title=Phosphorus Solubility in Response to Acidification of Dairy Manure Amended Soils |journal=Soil Science Society of America Journal |date=January 2008 |volume=72 |issue=1 |pages=238–243 |doi=10.2136/sssaj2007.0071N |bibcode=2008SSASJ..72..238P }}{{cite web |url=https://www.dpi.nsw.gov.au/agriculture/soils/improvement/n-acidify |title=Don't let nitrogen acidify your soil |website=Department of Primary Industries - New South Wales |access-date=2019-01-13}}

Acidification may also occur from nitrogen emissions into the air, as the nitrogen may end up deposited into the soil.{{cite press release |title=Acid Soils In Slovakia Tell Somber Tale |url=https://www.sciencedaily.com/releases/2008/11/081117153158.htm |work=ScienceDaily |publisher=United States Geological Survey |date=26 November 2008 }} Animal livestock is responsible for nearly 65 percent of man-made ammonia emissions.{{cite book |last1=Steinfeld |first1=Henning |last2=Gerber |first2=Pierre |last3=Wassenaar |first3=T. D. |last4=Castel |first4=Vincent |last5=de Haan |first5=Cees |title=Livestock's Long Shadow: Environmental Issues and Options |date=2006 |publisher=Food and Agriculture Organization |isbn=978-92-5-105571-7 |url=https://www.fao.org/4/a0701e/a0701e00.htm }}{{pn|date=January 2025}}

Anthropogenic sources of sulfur dioxides and nitrogen oxides play a major role in increase of acid rain production.{{clarify|but what is the mechanism of acidification of soils|date=August 2020}} The use of fossil fuels and motor exhaust are the largest anthropogenic contributors to sulfuric gases and nitrogen oxides, respectively.{{cite book |doi=10.1016/B978-0-12-656446-4.X5000-2 |title=Environmental Soil Chemistry |date=2003 |isbn=978-0-12-656446-4 }}{{pn|date=January 2025}}

Aluminum is one of the few elements capable of making soil more acidic.{{cite book |doi=10.1007/978-3-642-70874-9_23 |chapter=Air Pollution and Soil Acidification |title=Effects of Atmospheric Pollutants on Forests, Wetlands and Agricultural Ecosystems |date=1987 |last1=Abrahamsen |first1=G. |pages=321–331 |isbn=978-3-642-70876-3 }} This is achieved by aluminum taking hydroxide ions out of water, leaving hydrogen ions behind.{{cite journal |last1=Mossor-Pietraszewska |first1=T |title=Effect of aluminium on plant growth and metabolism. |journal=Acta Biochimica Polonica |date=30 September 2001 |volume=48 |issue=3 |pages=673–686 |doi=10.18388/abp.2001_3902 |pmid=11833776 |doi-access=free }} As a result, the soil is more acidic, which makes it unlivable for many plants. Another consequence of aluminum in soils is aluminum toxicity, which inhibits root growth.{{cite journal |last1=Delhaize |first1=E. |last2=Ryan |first2=P. R. |title=Aluminum Toxicity and Tolerance in Plants |journal=Plant Physiology |date=1 February 1995 |volume=107 |issue=2 |pages=315–321 |doi=10.1104/pp.107.2.315 |pmc=157131 |pmid=12228360 }}

Agriculture managements approaches such as monoculture and chemical fertilization often leads to soil problems such as soil acidification, degradation, and soil-borne diseases, which ultimately have a negative impact on agricultural productivity and sustainability.

{{main|Soil biodiversity#Acidification}}

Soil acidification can cause damage to plants and organisms in the soil. In plants, soil acidification results in smaller, less durable roots.{{cite journal |last1=Goulding |first1=K. W. T. |title=Soil acidification and the importance of liming agricultural soils with particular reference to the United Kingdom |journal=Soil Use and Management |date=September 2016 |volume=32 |issue=3 |pages=390–399 |doi=10.1111/sum.12270 |pmc=5032897 |pmid=27708478 |bibcode=2016SUMan..32..390G }} Acidic soils sometimes damage the root tips reducing further growth.{{cite journal |last1=Haling |first1=Rebecca E. |last2=Simpson |first2=Richard J. |last3=Culvenor |first3=Richard A. |last4=Lambers |first4=Hans |last5=Richardson |first5=Alan E. |title=Effect of soil acidity, soil strength and macropores on root growth and morphology of perennial grass species differing in acid-soil resistance |journal=Plant, Cell & Environment |date=March 2011 |volume=34 |issue=3 |pages=444–456 |doi=10.1111/j.1365-3040.2010.02254.x |pmid=21062319 |doi-access=free |bibcode=2011PCEnv..34..444H }} Plant height is impaired and seed germination also decreases. Soil acidification impacts plant health, resulting in reduced cover and lower plant density. Overall, stunted growth is seen in plants.{{cite journal |last1=Horne |first1=James E. |last2=Kalevitch |first2=Alexandre E. |last3=Filimonova |first3=Mariia V. |title=Soil Acidity Effect on Initial Wheat Growth and Development |journal=Journal of Sustainable Agriculture |date=3 May 1996 |volume=7 |issue=2–3 |pages=5–13 |doi=10.1300/j064v07n02_03 |bibcode=1996JSusA...7b...5H }} Soil acidification is directly linked to a decline in endangered species of plants.{{cite journal |last1=Roem |first1=W.J |last2=Berendse |first2=F |title=Soil acidity and nutrient supply ratio as possible factors determining changes in plant species diversity in grassland and heathland communities |journal=Biological Conservation |date=February 2000 |volume=92 |issue=2 |pages=151–161 |doi=10.1016/S0006-3207(99)00049-X |bibcode=2000BCons..92..151R }}

In the soil, acidification reduces microbial and macrofaunal diversity.{{cite book |last1=Slattery |first1=Bill |last2=Hollier |first2=Carole |title=Impacts of Acid Soils in Victoria: A Report |date=2002 |publisher=Department of Natural Resources and Environment, Rutherglen Research Institute |isbn=978-1-74106-246-5 |oclc=1034691965 }}{{pn|date=January 2025}} This can reduce soil structure decline which makes it more sensitive to erosion. There are less nutrients available in the soil, larger impact of toxic elements to plants, and consequences to soil biological functions (such as nitrogen fixation).{{Cite web|url=http://frds.dairyaustralia.com.au/wp-content/uploads/2012/01/DPI_Acid_Soils_Agnote_AG1182.pdf|title=Acid Soils|last1=Hollier|first1=Carole|last2=Reid|first2=Michael|date=April 2005 }} A recent study showed that sugarcane monoculture induces soil acidity, reduces soil fertility, shifts microbial structure, and reduces its activity. Furthermore, most beneficial bacterial genera decreased significantly due to sugarcane monoculture, while beneficial fungal genera showed a reverse trend.{{cite journal |last1=Zhang |first1=Shuting |last2=Liu |first2=Xiaojiao |last3=Zhou |first3=Lihua |last4=Deng |first4=Liyuan |last5=Zhao |first5=Wenzhuo |last6=Liu |first6=Ying |last7=Ding |first7=Wei |title=Alleviating Soil Acidification Could Increase Disease Suppression of Bacterial Wilt by Recruiting Potentially Beneficial Rhizobacteria |journal=Microbiology Spectrum |date=27 April 2022 |volume=10 |issue=2 |pages=e0233321 |doi=10.1128/spectrum.02333-21 |pmid=35254141 |pmc=9045175 }} Therefore, mitigating soil acidity, improving soil fertility, and soil enzymatic activities, including improved microbial structure with beneficial service to plants and soil, can be an effective measure to develop a sustainable sugarcane cropping system.

At a larger scale, soil acidification is linked to losses in agricultural productivity due to these effects.

Impacts of acidic water and Soil acidification on plants could be minor or in most cases major. In minor cases which do not result in fatality of plant life include; less-sensitive plants to acidic conditions and or less potent acid rain. Also in minor cases the plant will eventually die due to the acidic water lowering the plants natural pH. Acidic water enters the plant and causes important plant minerals to dissolve and get carried away; which ultimately causes the plant to die of lack of minerals for nutrition.{{cite journal |last1=Nikbakht |first1=Ali |last2=Kafi |first2=Mohsen |last3=Babalar |first3=Mesbah |last4=Xia |first4=Yi Ping |last5=Luo |first5=Ancheng |last6=Etemadi |first6=Nemat-allah |title=Effect of Humic Acid on Plant Growth, Nutrient Uptake, and Postharvest Life of Gerbera |journal=Journal of Plant Nutrition |date=14 November 2008 |volume=31 |issue=12 |pages=2155–2167 |doi=10.1080/01904160802462819 |bibcode=2008JPlaN..31.2155N }} In major cases which are more extreme; the same process of damage occurs as in minor cases, which is removal of essential minerals, but at a much quicker rate. Likewise, acid rain that falls on soil and on plant leaves causes drying of the waxy leaf cuticle; which ultimately causes rapid water loss from the plant to the outside atmosphere and results in death of the plant. To see if a plant is being affected by soil acidification, one can closely observe the plant leaves. If the leaves are green and look healthy, the soil pH is normal and acceptable for plant life. But if the plant leaves have yellowing between the veins on their leaves, that means the plant is suffering from acidification and is unhealthy. Moreover, a plant suffering from soil acidification cannot photosynthesize.{{cite journal |last1=Xiao |first1=Hong |last2=Wang |first2=Bing |last3=Lu |first3=Shunbao |last4=Chen |first4=Dima |last5=Wu |first5=Ying |last6=Zhu |first6=Yuhe |last7=Hu |first7=Shuijin |last8=Bai |first8=Yongfei |title=Soil acidification reduces the effects of short-term nutrient enrichment on plant and soil biota and their interactions in grasslands |journal=Global Change Biology |date=August 2020 |volume=26 |issue=8 |pages=4626–4637 |doi=10.1111/gcb.15167 |pmid=32438518 |bibcode=2020GCBio..26.4626X }} Drying out of the plant due to acidic water destroy chloroplast organelles. Without being able to photosynthesize a plant cannot create nutrients for its own survival or oxygen for the survival of aerobic organisms; which affects most species of Earth and ultimately end the purpose of the plants existence.{{Cite web|url=https://www.gardeningknowhow.com/plant-problems/environmental/acid-rain-damage.htm|title=What Is Acid Rain: Tips For Safeguarding Plants From Acid Rain Damage|website=Gardening Know How|date=15 September 2013 |language=en-US|access-date=2020-03-15}}

Soil acidification is a common issue in long-term crop production which can be reduced by lime, organic amendments (e.g., straw and manure) and biochar application.{{cite journal |last1=Jiang |first1=Yuhang |last2=Arafat |first2=Yasir |last3=Letuma |first3=Puleng |last4=Ali |first4=Liaqat |last5=Tayyab |first5=Muhammad |last6=Waqas |first6=Muhammad |last7=Li |first7=Yanchun |last8=Lin |first8=Weiwei |last9=Lin |first9=Sheng |last10=Lin |first10=Wenxiong |title=Restoration of Long-Term Monoculture Degraded Tea Orchard by Green and Goat Manures Applications System |journal=Sustainability |date=15 February 2019 |volume=11 |issue=4 |pages=1011 |doi=10.3390/su11041011 |doi-access=free |bibcode=2019Sust...11.1011J }}{{cite journal |last1=Tayyab |first1=Muhammad |last2=Yang |first2=Ziqi |last3=Zhang |first3=Caifang |last4=Islam |first4=Waqar |last5=Lin |first5=Wenxiong |last6=Zhang |first6=Hua |title=Sugarcane monoculture drives microbial community composition, activity and abundance of agricultural-related microorganisms |journal=Environmental Science and Pollution Research |date=September 2021 |volume=28 |issue=35 |pages=48080–48096 |doi=10.1007/s11356-021-14033-y |pmid=33904129 |bibcode=2021ESPR...2848080T }}{{cite journal |last1=Tayyab |first1=Muhammad |last2=Islam |first2=Waqar |last3=Arafat |first3=Yasir |last4=Pang |first4=Ziqin |last5=Zhang |first5=Caifang |last6=Lin |first6=Yu |last7=Waqas |first7=Muhammad |last8=Lin |first8=Sheng |last9=Lin |first9=Wenxiong |last10=Zhang |first10=Hua |title=Effect of Sugarcane Straw and Goat Manure on Soil Nutrient Transformation and Bacterial Communities |journal=Sustainability |date=6 July 2018 |volume=10 |issue=7 |pages=2361 |doi=10.3390/su10072361 |doi-access=free |bibcode=2018Sust...10.2361T }}{{cite journal |last1=Zhang |first1=Caifang |last2=Lin |first2=Zhaoli |last3=Que |first3=Youxiong |last4=Fallah |first4=Nyumah |last5=Tayyab |first5=Muhammad |last6=Li |first6=Shiyan |last7=Luo |first7=Jun |last8=Zhang |first8=Zichu |last9=Abubakar |first9=Ahmad Yusuf |last10=Zhang |first10=Hua |title=Straw retention efficiently improves fungal communities and functions in the fallow ecosystem |journal=BMC Microbiology |date=17 February 2021 |volume=21 |issue=1 |page=52 |doi=10.1186/s12866-021-02115-3 |pmc=7890633 |pmid=33596827 |doi-access=free }}{{cite journal |last1=Tayyab |first1=M |title=Biochar: An Efficient Way to Manage Low Water Availability in Plants |journal=Applied Ecology and Environmental Research |date=2018 |volume=16 |issue=3 |pages=2565–2583 |doi=10.15666/aeer/1603_25652583 |doi-access=free }} In sugarcane, soybean and corn crops grown in acidic soils, lime application resulted in nutrient restoration, increase in soil pH, increase in root biomass, and better plant health.{{cite journal |last1=Pang |first1=Ziqin |last2=Tayyab |first2=Muhammad |last3=Kong |first3=Chuibao |last4=Hu |first4=Chaohua |last5=Zhu |first5=Zhisheng |last6=Wei |first6=Xin |last7=Yuan |first7=Zhaonian |title=Liming Positively Modulates Microbial Community Composition and Function of Sugarcane Fields |journal=Agronomy |date=26 November 2019 |volume=9 |issue=12 |pages=808 |doi=10.3390/agronomy9120808 |doi-access=free |bibcode=2019Agron...9..808P }}{{cite journal |last1=Joris |first1=Helio Antonio Wood |last2=Caires |first2=Eduardo Fávero |last3=Bini |first3=Angelo Rafael |last4=Scharr |first4=Danilo Augusto |last5=Haliski |first5=Adriano |title=Effects of soil acidity and water stress on corn and soybean performance under a no-till system |journal=Plant and Soil |date=April 2013 |volume=365 |issue=1–2 |pages=409–424 |doi=10.1007/s11104-012-1413-2 |bibcode=2013PlSoi.365..409J }}

Different management strategies may also be applied to prevent further acidification: using less acidifying fertilizers, considering fertilizer amount and application timing to reduce nitrate-nitrogen leaching, good irrigation management with acid-neutralizing water, and considering the ratio of basic nutrients to nitrogen in harvested crops. Sulfur fertilizers should only be used in responsive crops with a high rate of crop recovery.{{cite report |last1=Wortmann |first1=Charles S |last2=Shapiro |first2=Charles A |date=June 2015 |title=Management strategies to reduce the rate of soil acidification |publisher=Cooperative Extension, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln |oclc=57216722 |url=https://extensionpubs.unl.edu/publication/g1503/2015/pdf/view/g1503-2015.pdf }}

By reducing anthropogenic sources of sulfur dioxides and nitrogen oxides, and with air-pollution control measures, let us{{who|date=December 2020}} try to reduce acid rain and soil acidification worldwide.{{cite press release |title=Acid Rain Effects on Forest Soils begin to Reverse |url=https://www.usgs.gov/news/national-news-release/acid-rain-effects-forest-soils-begin-reverse |publisher=U.S. Geological Survey |date=4 November 2015 }}

This has been observed in Ontario, Canada, over several lakes and demonstrated improvements in water pH and alkalinity.{{cite journal |last1=Keller |first1=Wendel (Bill) |last2=Heneberry |first2=Jocelyne H. |last3=Dixit |first3=Sushil S. |title=Decreased Acid Deposition and the Chemical Recovery of Killarney, Ontario, Lakes |journal=Ambio |date=May 2003 |volume=32 |issue=3 |pages=183–189 |doi=10.1579/0044-7447-32.3.183 |pmid=12839193 |bibcode=2003Ambio..32..183K }}

• {{annotated link|Acid sulfate soil}}
• {{annotated link|Alkali soil}}
• {{annotated link|Freshwater acidification}}
• {{annotated link|Ocean acidification}}

{{Reflist}}

• {{cite journal |last1=Fenn |first1=M. E. |last2=Huntington |first2=T. G. |last3=Mclaughlin |first3=S. B. |last4=Eagar |first4=C. |last5=Gomez |first5=A. |last6=Cook |first6=R. B. |title=Status of soil acidification in North America |journal=Journal of Forest Science |date=31 December 2006 |volume=52 |issue=Special Issue |pages=S3–S13 |doi=10.17221/10152-JFS |url=https://research.fs.usda.gov/treesearch/24312 |quote=Ca depletion is a primary mechanism of acid deposition effects in eastern North America|doi-access=free }}
• {{cite book |doi=10.1016/B978-0-443-14034-1.00009-5 |chapter=The Chemistry of Soil Acidity |title=Environmental Soil Chemistry |date=2024 |last1=Sparks |first1=Donald L. |last2=Singh |first2=Balwant |last3=Siebecker |first3=Matthew G. |pages=381–410 |isbn=978-0-443-14034-1 }}
• {{cite book |doi=10.1016/B0-12-348530-4/00173-9 |chapter=Acidity |title=Encyclopedia of Soils in the Environment |date=2005 |last1=Bolan |first1=N.S. |last2=Curtin |first2=D. |last3=Adriano |first3=D.C. |pages=11–17 |isbn=978-0-12-348530-4 }}
• {{cite book |doi=10.1016/B978-0-12-819555-0.00012-1 |chapter=Chemistry and toxicology behind chemical fertilizers |title=Controlled Release Fertilizers for Sustainable Agriculture |date=2021 |last1=Nadarajan |first1=Stalin |last2=Sukumaran |first2=Surya |pages=195–229 |isbn=978-0-12-819555-0 }}
• {{cite journal |last1=Hazlett |first1=Paul |last2=Emilson |first2=Caroline |last3=Lawrence |first3=Greg |last4=Fernandez |first4=Ivan |last5=Ouimet |first5=Rock |last6=Bailey |first6=Scott |title=Reversal of Forest Soil Acidification in the Northeastern United States and Eastern Canada: Site and Soil Factors Contributing to Recovery |journal=Soil Systems |date=27 August 2020 |volume=4 |issue=3 |pages=54 |doi=10.3390/soilsystems4030054 |doi-access=free |bibcode=2020SoiSy...4...54H }}

{{soil science topics}}

{{Authority control}}

{{DEFAULTSORT:Soil Acidification}}

acidification, soil

Category:Environmental issues with soil

Category:Soil degradation